1. Field of the Invention
This invention relates to a stepper, more particularly to a stepper which has a parallel-crank linkage that is capable of maintaining the pedals of the stepper in a horizontal state when the stepper is in use so as to enhance the safety features of the stepper.
2. Description of the Related Art
Referring to FIG. 1, a conventional stepper includes a support frame 1 having an upwardly extending front section 11, a pair of parallel foot beams 2 having end portions pivotally connected to a lower end portion of the front section 11 of the support frame I, and a pair of hydraulic cylinders 3. Each of the hydraulic cylinders 3 interconnects an intermediate portion of one of the foot beams 2 and an intermediate portion of the front section 11 of the support frame 1. A rope 4 has two ends respectively and fixedly connected to the intermediate portions of the foot beams 2 and extends over a pulley 12. The pulley 12 is mounted on the intermediate portion of the front section 11 of the support frame I above the foot beams 2 The front section 11 of the support frame 1 has a handgrip member 5 mounted securely on an upper end portion thereof. Referring to FIG. 2, the drawback of this stepper is that, when in operation, the user easily topples over because the foot beams 2 are inclined. As a result, stepping on the foot beams 2 may be dangerous.